Expert: Mark Sundberg - 8/9/2009

Question
Mark, I recently had my roof replaced due to hail damage and roofer recommended taking out my existing PAVs and putting in ridge vents only. Sounded good but now i have a hot attic and the upstairs AC unit can not keep up when the temp hits mid 90s. Builder now says he will put the PAVs back because i have a very steep roof with minimal place to put ridge vents. I have notice now that many houses with my style of roof have both. Is there any problem with having both? Hopefully they will be complemental to each other. The only other time i had this issue was when the attics weren't working. I plan to set the thermostat to 100 since attic temp below 110 seems to not be an issue.
Thanks,
Andy

Answer
Hi Andy,

They can interfere with each other, mostly because when the powered vents come on, they are going to suck a lot of air and they may suck it back through the ridge vent which might compromise their weather-resistance. To avoid the problem and improve the efficiency of all the vents, make sure there is sufficient intake venting and that the powered vents intake is as far from the ridge vents as possible.

Other than that, there shouldn't be much trouble.